Caseinolytic mitochondrial matrix peptidase X is essential for homologous chromosome synapsis and recombination during meiosis of male mouse germ cells.

ABSTRACT: Meiosis is the process of producing haploid gametes through a series of complex chromosomal events and the coordinated action of various proteins. The mitochondrial protease complex (ClpXP), which consists of caseinolytic mitochondrial matrix peptidase X (ClpX) and caseinolytic protease P (ClpP) and mediates the degradation of misfolded, damaged, and oxidized proteins, is essential for maintaining mitochondrial homeostasis. ClpXP has been implicated in meiosis regulation, but its precise role is currently unknown. In this study, we engineered an inducible male germ cell-specific knockout caseinolytic mitochondrial matrix peptidase X (ClpxcKO) mouse model to investigate the function of ClpX in meiosis. We found that disrupting Clpx in male mice induced germ cell apoptosis and led to an absence of sperm in the epididymis. Specifically, it caused asynapsis of homologous chromosomes and impaired meiotic recombination, resulting in meiotic arrest in the zygotene-to-pachytene transition phase. The loss of ClpX compromised the double-strand break (DSB) repair machinery by markedly reducing the recruitment of DNA repair protein RAD51 homolog 1 (RAD51) to DSB sites. This dysfunction may be due to an insufficient supply of energy from the aberrant mitochondria in ClpxcKO spermatocytes, as discerned by electron microscopy. Furthermore, ubiquitination signals on chromosomes and the expression of oxidative phosphorylation subunits were both significantly attenuated in ClpxcKO spermatocytes. Taken together, we propose that ClpX is essential for maintaining mitochondrial protein homeostasis and ensuring homologous chromosome pairing, synapsis, and recombination in spermatocytes during meiotic prophase I.

The histone modification reader ZCWPW1 is required for meiosis prophase I in male but not in female mice.

Meiosis is a specialized type of cell division that creates haploid germ cells and ensures their genetic diversity through homologous recombination. We show that the H3K4me3 reader ZCWPW1 is specifically required for meiosis prophase I progression in male but not in female germ cells in mice. Loss of Zcwpw1 in male mice caused a complete failure of synapsis, resulting in meiotic arrest at the zygotene to pachytene stage, accompanied by incomplete DNA double-strand break repair and lack of crossover formation, leading to male infertility. In oocytes, deletion of Zcwpw1 only somewhat slowed down meiosis prophase I progression; Zcwpw1-/- oocytes were able to complete meiosis, and Zcwpw1-/- female mice had normal fertility until mid-adulthood. We conclude that the H3K4me3 reader ZCWPW1 is indispensable for meiosis synapsis in males but is dispensable for females. Our results suggest that ZCWPW1 may represent a previously unknown, sex-dependent epigenetic regulator of germ cell meiosis in mammals.

[Straw Composts with Composite Inoculants and Their Effects on Soil Carbon and Nitrogen Contents and Enzyme Activity].

The utilization of straw resources is of great significance to agricultural environmental protection and sustainable agricultural development. Based on the isolated 15 high-efficient cellulose degrading bacteria in the laboratory, the composite inoculants (JFB-1) which can effectively degrade crop straw were screened, and the effects of straw composts with the composite inoculants on soil carbon and nitrogen contents and enzyme activity were studied. The results showed that the composite inoculants could accelerate straw decomposition for 1-2 d during single fermentation period, and the organic matter contents in straw composts reached 403.5-515.1 g·kg-1, while the ratio of carbon and nitrogen decreased from 10.53 to 15.30. The pot experiments found that the application effects of rice straw composts were generally better than those of corresponding asparagus straw composts. Compared with the control compost of rice straw, when the application amount of rice straw compost using the composite inoculants was 150 g·kg-1, the contents of soil organic matter and total nitrogen increased by 33.5% and 7.3%, and soil urease and cellulase activities increased by 16.7% and 30.8%, respectively. Compared with no fertilization treatment, the application of straw composts could improve soil microbial community structure, and increase microbial diversity indices. When the application amount of rice straw compost using the composite inoculants was 100 g·kg-1, the biomass of common Chinese cabbage cultivated for 30 d increased by 46.4% compared to the control compost of rice straw. These results indicated that the composite inoculants have great application potential in straw composts.

Role of miR-126 in effect of biological behaviour and epithelial to mesenchymal transition (EMT) in human colon cancer cells / 中国免疫学杂志

Objective:To investigate the expression of miR-126 in human colon cancer cell lines with different metastatic potential and its effect on the proliferation, invasion and metastasis of colon cancer cells, and to explore the possible mechanism.Methods:The expression of miR-126 in human colon cancer cell lines(SW480,SW620 and HCT116) was determined by Real-time fluorescence quantitative PCR.miR-126 mimics were transiently overexpressed in SW620 cells throuIgh liposome transfection and the negative control group was set up.The proliferation ability of cells was detected by CCK8 method and the mobility of cells was detected by wound healing assay and Transwell migration and invasion assay.The expression of E-cadherin,Vimentin was determined by Western blot.Results:The expression of miR-126 was decreased in SW620 and HCT116 cells with high metastatic potential compared SW480 cells with low metastatic potential.The overexpression of miR-126 significantly inhibited the proliferation,migration and invasion ability of SW620 cells and Western blot indicated that miR-126 overexpression increased the expression of E-cadherin and decreased the expression of Vimentin in SW620 cells,which was significantly different from that of negative control(P<0.05).Conclusion:Low expression of miR-126 is closely related to metastasis of colon cancer and the effect of miR-126 on the biological behavior of colon cancer cells may be mediated by the regulation of the EMT process.

[Progress in the study of near-infrared fluorescent probes for the detection of ß-amyloid deposition in Alzheimer's disease].

Alzheimer's disease (AD) is the most common cause of cognitive impairment in older people. With the aging of society is more and more serious, AD caused great burden to patients and society. A ß is a classical biomarker of AD, which has been widely used in clinical diagnosis of AD patients. Compared with positron emission tomography (PET) and single photon emission computed tomography (SPECT), near infrared fluorescence imaging has many advantages including highly sensitive, non-invasive, safety and inexpensive. Therefore, many research groups have focused on developing the molecular probes of near-infrared fluorescence (NIRF) imaging. In this article, we will review the progress of the probes of NIRF.